Sucking carbon dioxide and other greenhouse gases from smokestacks and burying them underneath the ground is a key technology cited by politicians and scientists as a way to help combat climate change. One open question is where best to store the CO2. A recent analysis points to the volcanic rock off the East Coast of the U.S.

Such rock, known as basalt, might be better than other sites, such as deep saline aquifers or nearly empty oil wells, because the rock not only stores CO2 but also over a relatively short period of years forms carbonate minerals out of it—in other words, limestone. And coastal basalt has the added benefit of having an overlying ocean, which acts as a second barrier of protection against the gas leaking out.

Research led by geophysicist David S. Goldberg of Columbia University’s Lamont-Doherty Earth Observatory had previously shown that basalt lies off the West Coast of California, Oregon and Washington. His group’s latest search has turned up vast deposits in the East off the coast of Georgia, Massachusetts, New Jersey, New York and South Carolina. One formation off of New Jersey could hold as much as one billion metric tons of CO2, report Goldberg and his team in the online January 4 Proceedings of the National Academy of Sciences USA. Of course, the world’s nations emit over 30 billion metric tons of CO2 a year.

If scientists can show that CO2 stays put underground—experiments are under way off the coast of Oregon and in Iceland—then basalt could become important considering how widespread it is, points out Klaus S. Lackner, director of the Lenfest Center for Sustainable Energy at the Earth Institute. “The ­Siberian basalt traps, the Deccan flats in India—there are enormous amounts of basalt” around the world, he notes.